As more people manage data using computer applications, like personal data in personal information management (PIM) applications, the cases where people want to share such information with other people grow. For example, people might like to be able to share data items, including contacts, calendar items, and so on, with family members, work colleagues, and other acquaintances. They may want to share different sets of information with different sets of people, and they may want to receive changes to the data made by the people with which they share their data. In addition, people that want to share information often use different applications and environments, and may have their data stored in different formats. For example, a person might use one type of PIM application at work and another type of PIM application at home, while their friend uses yet another type of PIM application. However, the same person may still want to share information between all of these applications.